Sand in the Sahara Desert doesn’t always stay put. Tiny particles can be lofted into the air, eventually landing elsewhere in that vast sandy desert. Sometimes dust from the Sahara traverses an entire ocean. That was what happened in July 2012, when a dust plume extended across the Atlantic Ocean toward the Caribbean Sea and Florida.

This color-coded map is made from data collected by the Ozone Mapper Profiler Suite (OMPS) on the SuomiNational Polar-orbiting Partnership (S-NPP) satellite. It shows relative aerosol concentrations across the Atlantic Ocean on July 21, 2012. Lower concentrations appear in yellow, and greater concentrations appear in dark orange-brown. Areas in grey represent data that have been screened out due to sunglint (reflection of sunlight) or other factors.

The dust followed a southward-sweeping arc over the ocean, and remained relatively thick northeast of the Caribbean islands. In the Western Hemisphere, Saharan dust has costs and benefits. Heavy dust transport to the region has coincided with coral declines, yet without regular dustings, some Caribbean islands would be barren rocks devoid of soil. Saharan dust also provides soil to the Amazon Rainforest.

For residents of southern Florida, dust from the Sahara can aggravate breathing difficulties. In July 2012, National Weather Service meteorologists warned that people with respiratory problems should take precautions, but explained that the dust transported across the Atlantic Ocean typically remains 5,000 to 6,000 feet (1,500 to 1,800 meters) above ground. A more likely consequence of the dust would be a “milky or hazy appearance” to southern Florida’s skies.

References

Holmes, H. (2001). The Secret Life of Dust. John Wiley and Sons, Inc., Hoboken, New Jersey.